A known type of center pillar structure for a vehicle is shown in FIG. 8, in which an anchor rail a, supporting a seat belt anchor in a vertically movable manner, is fixedly mounted on an interior surface of an inner panel c of a center pillar b.
In the above prior art structure, the following problems are encountered: The size of the center pillar b in a widthwise direction of the vehicle cannot be increased very much, because the anchor rail a is mounted on the interior surface of the inner panel c. Therefore, to assure the rigidity of the center pillar b, the size of the center pillar b in a lengthwise direction of the vehicle must be increased. Eventually, the center pillar b may be thickened and hence, with a sashless type of door, the center pillar mostly appears externally, which results in the vehicle having an injured appearance.